Question

1. Power generation by natural gas or other petroleum product fired steam power plant is the most comment way of producing energy in most parts of the world

a. Sketch steam power plant and discuss the function of each unit Operation in the process

(

b. What are the major operational and safety challenges in steam power plants )

c. Pumps are the most important fluid movers in process industries, discuss the various types of Pumps you find in steam power plant and their volatility.

d. Discuss various types of values used in steam power plants. (

e. What are the environmental challenges or problems related to steam power plants (

  

2. Petroleum refining process involves distillation as the most important separation unit for purification of different products based on their volatility.

a. Discuss various types of distillation processes you may find in petroleum refineries ()   

b. What can be done to improve purity of a top product in a distillation column  (

)

c. What will be the effect of excessive reflux ratio in a distillation column    

d. What are the operational factors affecting the efficiency of a distillation column

)

e. Discuss the problems of flooding and weeping in a distillation column  )

3. Safety is one of the most important concerns in any occupational environment particularly in process industries.

a. What the main things that a safety training program for operators should involve)

b. What are the major engineering control methods to ensure safety in process industries.

Answer 1

1.

(a)

• BOILER : Boiler has the function to convert water into steam. The process of change of water to vapour done by heating the water in the pipes with heat from burning fuel.
• BOILER FEED PUMP : Function is to feed the water to be steamed in the boiler of thermal power plant.
• ECONOMIZER : The economizer is a feed water heater, deriving heat from the flue gases.
• STEAM TURBINE : Steam turbine working to change the heat energy contained in the steam into rotary motion. Steam with high pressure and temperature were directed to push turbine blades mounted on the shaft, so the shaft rotates.
• PREHEATER : The flue gases coming out of the economizer is used to preheat the air before supplying it to the combustion chamber.
• SOOT TOWERS : The fuel used in thermal power plants causes soot and this is deposited on the boiler tubes, economizer tubes, air pre heaters, etc. This drastically reduces the amount of heat transfer of the heat exchangers.
• CONDENSER : The use of a condenser in a power plant is to improve the efficiency of the power plant by decreasing the exhaust pressure of the steam below atmosphere.
• COOLING TOWER : The importance of the cooling tower is felt when the cooling water from the condenser has to be cooled.

(b)   Major operational and safety challenges in steam power plants :

1. Occupational Hazards depending upon occupation of an employee may be exposed to these hazards ( Physical hazards,Heat ,Noise etc)

2. Chemical Hazards Smoke: Inhalation of smoke which can contain poisonous gaseous fumes also and can have effects on our health. Fumes: fumes emanating from liquid chemicals can cause ill effects on our health when inhaled.

3. Industrial noise can give rise to deafness Non auditory effects are irritation, nervousness, annoyance, fatigue, inefficiency etc.

c)

• Boiler circulating pumps : They pump water through a boiler and hence helps to increase the effectiveness of the boiler.
• Condensate pumps : They collect the saturated water from the condenser and pump it to back into the boiler feed pump. The operationg pressure is extremely low suction pressures.
• Condenser circulating pumps : They deliver cool water from freshwater sources near the power plant and then pump it through the condenser to condense exhaust steam from the turbine.

(d) These are the types of valves most commonly used in thermal power plant :

1. Gate and globe valves
2. Check valve-flap type, float type diagram type, ball type
3. Pressure &temp control valve
4. Diaphragm valve
5. Pneumatic operated valves

(e)  Environmental challenges or problems related to steam power plants :

1. Carbon dioxide is one of the main gases that is released from the burning of the fossil fuels and thermal power plants are one of the main contributors to the increased carbon dioxide levels throughout the world.

2.  Sulfur dioxide is another gas that is released from power plants.

3. Fly ash generation.

4. Fugitive Dust , Noise etc.